Terpin esters



Patented Feb. 18, 1941 r q I I UNITED sTATEs PATENT OFFICE TERPIN Es'rEas Joseph N. Borglin, Wilmington, De'l., assignor to' Hercules Powder Company, Wilmington, DeL', a corporation of Delaware No Drawing. Application April 14, 1939,

Serial No. 267,913

13 Claims. (Cl. 260-489) This invention relates to esters of terpin and The terpin ester produced by this method may toan improved method for their preparation. be recovered from the reaction mixture, by wash- Terpin is readily dehydrated upon heating to ing the reaction mixture with water, a dilute elevated temperatures and it has heretofore been mineral acid, for example, dilute hydrochloric found difficult to prepare'the terpin diacetate in acid, and then with water, and finally recovering 5 more than minor yields and impossible to prepare the, terpin ester as a water immiscible oil. Alterthe. corresponding propionate and butyrate. natively, the terpin ester may be recovered from NOW,.I havefound that I can prepare the terpin the reaction .mixture by distilling the volatile esters of the lower fatty acids by reacting terpin constituents from the terpin ester, at reduced with the anhydride of a lower fatty acid in the pressure, if desired. When inorganic catalysts presence of amildbasic catalyst. In this WayIhave have been :used in the reaction, they will largely succeeded in preparing terpin. dipropionate and crystallize out and may then be removed by filtraterpin dibutyrate in good yields. I have also suction or decantation of the liquid product. Subceeded in preparing terpin diacetate in much betstantially complete removal of inorganic catalysts 9.91381 yields than. have heretofore been obtained. may be effected by diluting of the crude product "By the: method in accordance with this invenobtained after distilling volatile materials from tion, terpin reacted with the anhydride of a thereaction'mixture with such organic solvents lower fatty acid in the presence of a mildl'y'basic asabenzene, petroleum ether, carbon tetrachloride,

catalyst. etc.,;filtering toremove the precipitate formed, The mildly basiccatalyst which I utilize in this and, evaporating the added solvent. 29 reaction may be a basic inorganic salt, such as, The method in accordance withthis invention for example, sodium acetate, potassium acetate, isfurther illustrated by the, following examples: sodiumformate, potassium formate, sodium pro- Ex m z 1 1 pionate, potassium propionate, sodium butyrate, pe I potassium-butyrate. Again, it may be a weak. -Sixl1undred parts by weight of terpin,1300 2 organic. base, suchas, for example, pyridine, parts by weight of acetic anhydride and 50 parts quinoline, pyrrol, strychnine, tetrahydro quinoby Weight of anhydrous sodium acetate were line, etc. heated for 136 hours at 95 C. and 18 hours at The anhydride of a lower fatty acid anhydride 110 C. The resulting reaction mixture was 30 which I utilize may be, for example, acetic anwashed with water, with aqueous sodium carbon- 30 hydride, propionic anhydride, butyric anhyate and again with Water, to yield 677 parts of dride, etc. terpin diacetate.

The terpin utilized in this reaction can be con- Example 2 veniently obtained by the partial dehydration of. terpin hydrate. Thus, for example, terpin may Three hundred parts by welght of terp n, 50 30 be obtained by heating terpin hydrate to a te-mparts by weight of acetic anhydride and 750 parts perature of about 113 C. until the evolution of by weight of pyridine were allowed to stand 48 water ceases. hours at F., 16 hours at 90 C. and finally re- In carry ng ou the method in accordance w h fiuxed 16 hours. The reaction product was then this invention, a mix ur 0f t p and e anhywashed with water, with dilute hydrochloric acid dride of a lower fatty acid anhydride is heated, and finally t Water to give. an 36% yield 336 p b y under IefiuX, a temperature Within parts by weight) of terpin diacetate. This product the range of about C. to about 175 C. and gave the following analyses. preferably within the range of about 125 C. to

about for a period of about 8 to 1 .Zi?$fi$2?id2$ ??f::3:::::::::::: 1.4555 about hours. In carrying out this re,

action stoichiometric proportions of the two reacp 3 tants may be used, but in general I prefer to use Terpin dibutyrate was prepared by heating 150 50 an E C 0f the a y 0f the 10WB1 fatty parts by weight of terpin, 200 parts by weight of 50 acid. I may use an amount of the mildly basic butyric anhydride and 10 parts by weight of socatalyst within the range of about 0.1% to about dium acetate at 95 C. for 15 hours and then at 25% by Weight of the terpin present, and prefer- C. for 16 hours. The crude product was waably an amount within therange of about 3% to ter washed, washed with aqueous sodium car- 65 about 12% by weight of the terpin present. bonate and finally with Water, to yield 97 parts 55 by weight of terpin dibutyrate. The terpin dibutyrate had the following properties:

Refractive index at 20 C 1.465

Specific gravity at 15.6 C./15.6 C 0.9551

Example 4 Terpin dipropionate was prepared by heating a mixture of 400 parts by weight of propionic anhydride, 300 parts by weight of terpin, and 20 parts by Weight of anhydrous sodium acetate for 24 hours at -95 C. for 16 hours at C., and finally for 8 hours at C. The reaction mass was cooled to room temperature, washed with water, then washed with a water solution of sodium carbonate, and again washed with water. The product was filtered and dried by heating at 100 C., at a slightly reduced pressure. As a result of this treatment, 264 parts by weight of terpin dipropionate were obtained, the product having the following properties:

Refractive index at 20 C 1.463 Specific gravity at 15.6 C./15.6 C 0.9880

It will be appreciated that the method in accordance with this invention may be utilized to prepare chemically mixed lower fatty acid terpin esters such as terpin acetate-butyrate, terpin acetate-propionate, terpin butyrate-propionate, etc. Instead of a single fatty acid anhydride, two fatty acid anhydrides may be used in equimolecular proportion, or, if desired, an additional slight excess of the anhydride having the higher molecular weight may be used. Chemically mixed fatty acid anhydride may also be used in an equivalent manner.

The terpin esters produced in accordance with this invention are valuable insecticides. They are also solvents for nitrocellulose and cellulose acetate, and therefore valuable in the formulation of cellulose ester compositions in which relatively high boiling solvents are desired.

It will be understood that the details and examples given hereinbefore are illustrative only and in no way limiting on my invention as broadly described hereinbefore and in the appended claims.

What I claim and desire to protect by Letters Patent is:

1. Terpin dibutyrate.

2. Terpin acetate-butyrate.

3. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with the anhydride of a lower fatty acid in the presence of a mildly basic catalyst.

4. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with the anhydride of a lower fatty acid in the presence of a mildly basic inorganic salt.

5. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with the anhydride of a lower fatty acid in the presence of a weak organic base.

6. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with the anhydride of a lower fatty acid in the presence of sodium acetate.

7. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with the anhydride of a lower fatty acid in the presence of pyridine.

8. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with two lower fatty acid anhydrides in the presence of a. mildly basic catalyst.

9. A method for the preparation of a terpin lower fatty acid ester which comprises reacting terpin with two lower fatty acid anhydrides in the presence of sodium acetate.

10. A butyrate ester of terpin.

11. A method for the preparation of terpin diacetate which comprises reacting terpin with acetic anhydride in the presence of a mildly basic catalyst.

12. A method for the preparation of terpin diacetate which comprises reacting terpin with acetic anhydride in the presence of sodium acetate.

13. A method for the preparation of terpin diacetate which comprises reacting terpin with acetic anhydride in the presence of pyridine.

JOSEPH N. BORGLIN. 

